Fire-extinguishing apparatus



Feb. 21,, 1950 N. J. THOMPSON FIRE EXTINGUISHING APPARATUS Filed Aug. 30, 1946 F2 2 56 Z07 A l b7 'r/Zan' J??? 0717 275075 [If/ r Patented Feb. 21, 1950 FIRE EXTINGUISHING APPARATUS Norman J Thompson, Newton, Mass., assignor to Factory Mutual Research Corporation, Boston, Mass, a corporation of Massachusetts Application August 30, 1946, Serial No. 693,861

2 Claims.

This invention relates to apparatus for extinguishing fires in rooms of various kinds, including large factory places with ceiling (or roofs) overhead, and more particularly to apparatus for extinguishing fires in pans or vats of flammable liquids such as acetone, ether, benzol, gasoline, etc., which fires are extremely difiicult to extinguish.

Objects of the invention are to provide apparatus which is simple and inexpensive to manufacture, which is easy to install, which is reliable and economical in use, which is quick and effective in action, which is universally applicable to all flammable liquids, which has little if any tendency to flood the premises, which can be controlled either automatically by heat responsive means or manually by hand operated valves and which is generally superior to prior apparatus of the kind referred to.

The present invention involves the combination of a duct extending downwardly from a location near the ceiling (or roof) and. a nozzle for directing a jet of fire-extinguishing material downwardly through the duct, the upper end of the duct having an opening adjacent the ceiling so that the products of combustion which rise to the ceiling from a fire in the room are drawn into the upper end of the duct by the jet and returned to the fire, thereby to smother the fire. Preferably the nozzle is located at the upper end of the duct, both ends of the duct are flared, the axis of the duct extends approximately vertically, and the duct extends throughout a large proportion of the vertical dimension of the room.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which Fig. l is a vertical section;

Fig, 2 is a horizontal section on the line 2-2 of Fig. l; and

Fig. 3 is a view from the line 3-3 of Fig. 1.

In the particular embodiment of the invention chosen for the purpose of illustration 1 represents the floor of a room and 2 the ceiling, 3 are side walls of the room, and 4 is a tank of flammable liquid such as gasoline. Mounted over the tank 4 is a vertical duct 5, the duct being mounted in any suitable manner as by brackets 6 attached to the ceiling. The upper end of the duct should be near the ceiling and the lower end of the duct should be as near as practicable to the vat 4, although it is usually desirable to keep the lower end of the duct slightly above the head level of the operators working around the tank 4. Both ends of the duct are flared, the lower end 9176i?!- ably being flared somewhat more than the upper end substantially to cover the entire area of the liquid in the vat 4. Mounted in the axis of the duct 5 is a nozzle 1 which is preferably located at the upper end of the duct and which may comprise a standard discharge horn for carbon dioxide. A pipe 8 through which the nozzle 1 is supplied may be provided with a suitable valve and the valve may be controlled by a thermostat located at a convenient position in the room, preferably near the ceiling 2 at one side of the duct 5. Instead of using a valve in the pipe 8 the nozzle may be one of the well known automatic types. Depending from the ceiling 2 are baffle plates 9 which tend to confine the products of combustion rising from a fire in the tank 4 to the ceiling.

When a fire occurs the jet from the nozzle 1 draws into the upper end of the duct 5 the products of combustion which rise from the fire to the ceiling, and when returned to the fire these products of combustion tend to smother the fire. The jet may comprise carbon dioxide, fire-extinguishing powder, water, steam or other material. The greater the distance from the lower end of the duct to the tank, the higher should be the pressure in the pipe 8. For example with a distance of '7 feet the pressure may be 40 pounds and with a distance of 9 feet the pressure may be 55 pounds. The diameter of the duct should be proportional to the horizontal dimensions of the tank. For example with a tank 6 feet wide and 8 feet long the diameter of the duct may be on the order of 3 feet to 4 feet. It has been found that a fire may be quickly extinguished when the oxygen content near the ceiling has been reduced by only a few per cent.

In the case of large tanks more than one nozzle may be required to cover the entire area of the tank, in which case the nozzles are spaced horizontally above the tank. Each nozzle may have its own duct or several nozzles may be disposed within a duct large enough to cover the entire tank.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. For extinguishing a fire inside aroom, the combination of a duct open at both ends, means for mounting the duct directly over the fire with its axis extending approximately vertically, and a nozzle approximately in said axis for directing a jet of fire-extinguishing material along the duct and thence to the fire to cause the combustion products of the fire to spread outwardly in different directions, the upper end of said duct being close to the ceiling but spaced therefrom so that the products of combustion which rise to the ceiling are drawn inwardly from said different directions into the upper end of said duct by said jet and directed from the lower end ofthe duct back to the fire.

2. For extinguishing a fire inside a room, the combination of a duct open at bothends, means for mounting the duct directly over the fire with its axis extending approximately vertically, and a nozzle approximately in said axis for directing a jet of fire-extinguishing material downwardly to the fire to cause the combustion products of the fire to spread outwardly in difierent directions,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Thompson May 19,

Number 

